4 CONTENTS. 



Notes on the Nesting Activities of the Noddy and Sooty Terns — Continued. Page. 



Recognition of the young 76 



Instinct and habit in the nesting activities 80 



Modifiabihty of instinctive activities 80 



Integration of complex habits 82 



Studies on the Spectral Sensitivity of Birds 85 



Methods of studying spectral sensitivity 87 



The limits of the chick's spectral sensitivity 90 



Limits at the Red end 91 



Limits at the Violet end 94 



Relative stimulating effect of monochromatic light 96 



Ri5sum6 of results of study on chick 98 



Limits of spectral sensitivity in the Homing Pigeon 99 



Limits at the Violet end 99 



Limits at the Red end 101 



R6sum(? of Tests on Pigeon 104 



The Acquisition of Skill in Archery 105 



Equipment 108 



Computation of avci-ages and comparison of individual and group records 109 



A comparison of unlike groups of individuals under the same conditions of 



practice Ill 



Distribution of practice and rate of learning 113 



Purpose and method of the experiment 113 



Comparability of the groups studied 114 



Conditions affecting improvement 116 



Effect of the distribution of practice 120 



The problem of "distribution-rate" relation 124 



Resume of results 127 



Bibliography 128 



